$\left[\begin{array} {ccc} -4& 2& 2& 9& 9\\ -7& -2& 0& 3& 9\\ -5& 3& -7& 1& -9\\ 3& 2& -1& 9& 1 \end{array}\right]$ What are the dimensions of the matrix?
Explanation: The first dimension is the number of rows in the matrix. There are $4$ rows. The second dimension is the number of columns in the matrix. There are $5$ columns. In conclusion, the dimensions of the matrix are $4\times 5$.